Internal combustion engine piston



April 3, 1945. 5, Wm 2,372,993

INTERNAL-COMBIJSTION ENGINE PISTON I Filed Jan. 14, 1944 INVEN TOR.

fame)" W221" BY V awe/20am- Patented Apr. 3,4945

UNITED-STATES harem orr cs 2,872,998 INTERNAL COMBUSTION ENGINE PISTON James Weir, University Heights, Ohio, assign" to Aluminum Company of America. Pittsburgh, Pa., a-corporatlon of Pennsylvania.

Application January 14, 1944, Serial No. 518.219

4 Claims. (Cl.128-176) This invention relates to pistons for internal combustion engines, and relates particularly to a piston embodying an arrangement for dissipating heat from the piston head.

It is an object of this invention to provide a piston having improved means for extracting heat from the piston head. It is 'a further object of this invention to providean internal combustion engine piston adapted for improved removal of heat from the piston head through the wrist pin of the piston. It is a further object of this invention to provide a piston. wrist pin. and connecting rod assembly whereby heat is transmitted Fig.. 1 is a vertical sectional view of the piston and connecting rod;

Fig. 2 is a vertical longitudinal section of the assembly, taken on the line 11-11 of Fig. 1: and

Fig. 3 is a bottom plan view of the piston shown in Figs. 1 and 2.

Referring to the drawing, the piston comprises a head or end wall I having a piston ring flange 2 depending therefrom with the usual piston rins grooves therein, and a skirt 8 integral with the ring flange and carrying a pair of wrist pin bosses l and d integral therewith. A wrist pin I is journalled in the wrist pin bosses and maintained in place by lock rings 8, and a connecting-rod 1 (shown partly broken away) is journalled on the wrist pin intermediate the wrist pin bosses,

' there being a bearing s provided between the wrist pin and the head of the connecting rod.

An aperture 9 extends through the head of the connecting red I adjacent the underside of the piston head I, and also extends through the wall of the bearing 8. The underside of the piston of the aperture 0. at a point above the axis of the wrist pin, are a pair of chambers l2 and i2 formed by the bearing 8 and grooves in the connecting red head. and communicating with an axial passage ii in the connecting rod through a cross passage I which is likewise defined by the bearing 8 and a groove in the head of the connecting rod. The opposite end (not shown) of the connecting rod is ioumalled on the crank shaft of the engine, and the passage l8 communicates with an oil passage in the crank shaft inamannerwell known intheart. Asaresult, lubricating 'oil from the oil system of the engine can be pumped through the passage is and the chambers If and I! under pressure with sumcient velocity that the oil flows over the cooling fins and exposed surface of the wrist pin, with a resulting extraction of heat from the cooling fins by the oil, as well as lubrication of the contactingsurfaces of the wrist pin and fins. Pref-- erably the bearing I is provided with openings II which register with the chambers l2 and I 2' and thus permit oil from those chambers to lubricate the contacting surfaces of the wrist pin and bearing. The chambers l2 and li'extend more than half way around the wrist pin. thereby insuring that oil therefrom will flow over the upperhalf of the wrist pin.

The piston i preferably made of metal having high heat conductivity, such as aluminum. It may be produced satisfactorily by casting or by forging. In either case, the fins l0 may be formed in the casting or forging operation, or by machining them into a solid boss formed on the interior of the piston head during forging or casting. r

In the operation of the assembly, heat imparted to the pistonhead by burning of gases flows through th fins III to the relatively cooler wrist pin, whence it is chiefly transmitted to the head I is provided with a plurality of depending fins. ll integral therewith which extend through the aperture 8 and contact the wrist pin 5. The lower ends of the fins l0 conform in contour to the curve of the wrist pin to permit the fins to contact a sizable portion of the circumference of the wrist pin, the aperture 9 being suillciently wide to accommodate the fins during oscillation of the head of the connecting rod on the wrist pin. Opening into the area defined by the walls piston skirt and piston rings by way of the wrist pin bosses. As a result of such extraction of heat, the temperature of the piston head is lowered. Furthermore, the oil flowing over the iins ill from the chambers l4 and It not only lubricates the surface of the wrist pin which is contacted by the fins I I. but also absorbs heat from the fins; The oil then falls into the crank case and eventually is carried to the oil cooler of the engine and cooled for re-circulation through the engine's oil system.

Various modifications can be made in the assembly described above without departing mm the invention as defined in the following claims;

I claim:

1. In the combination comprising a piston having a piston head, a pair or oppositely disposed wrist pin bosses, and a wrist pin iournalled in said bosses, means depending from said head, and contacting said. wrist pin intermediate said wrist pin bosses, for conducting heat from the said piston head to the said wrist pin.

2. In the combination comprising a piston having a piston head, a pair of oppositely disposed wrist pin bosses, and a wrist pin journalled in said bosses; a plurality of tins depending from said head and contacting said wrist pin" interme- 1 diate said wrist pin bosses.

3. In the combination comprising a piston having a piston head. a pair of oppositely disposed astsms said head and extending through an aperture in.

said connecting rod into contact with said wrist pin intermediate said wrist pin bosses.

JAMES WEIR. 

